Temp gauge confusion

[rdstudio]

Hello!

So from long time my car always run hot (at least that is what I was thinking when cooling at gauge) - but when metering by IR gun, all temperatures was OK. So I was driving like that with wrong readouts, but this year I want to sort it out finally.

So few days ago I made radiator flush, installed new TS17 temp sender unit.
Nothing has changed, also showing that is running over 210-220 at idle. IR gun showing way less like 180.

So I read that you can test gauge by feeding ohm to it. So I did and when feeding 25 ohms - gauge is reading in the middle. Which is correct. Also feed 10 omh and was reading full.

So next test I did, was run idle a little, make engine hot and than check how many ohms I have from my temp sender unit + make photo of gauge.

And there is where confusion comes.

When I feed to gauge 25 ohms - it is showing proper half of temp gauge.

When sender is sending 40 ohms - it is showing center of temp gauge (should be like less than that)
When sender is sending 34 ohms - its is showing MORE than half.

Why 25 ohms which I feed is showing less than 34 ohms from temp sender unity?!

Really I'm about to order mechanical temp gauge because I keep thining my car is overheating with all those incorrect readings.

Photos :

 

[dadsbee]

The way it's supposed to work! 10 ohms is full stoke on the gauge and 74 is stone cold (exact same as fuel gauge and oil pressure gauges). A good temp sender will have around 300 ohms at room temp of about 68f.

As the sender heats up the resistance lowers...

 

[rdstudio]

and 34 ohms should show more on gauge than 25? I guess no

 

[dadsbee]

I saw the 40 and 34 and resistance going down.. gauge went up. I'm not following how you are "feeding" resistance.

 

[davek]

My gauge on the Bee is off so I added a mechanical gauge. Hope you get it figured out.

 

[rdstudio]

I saw the 40 and 34 and resistance going down.. gauge went up. I'm not following how you are "feeding" resistance.

40 and 34 are read from sender - connected ohm meter read ohms and made photos of gauge
25 is feeded by connecting 4 resistors that create 25ohm reading into sender wire.

 

[rdstudio]

My gauge on the Bee is off so I added a mechanical gauge. Hope you get it figured out.

did you connect sender near alternator bracket into 3/8" NPL ?

 

[davek]

Bees a BB and there is a place on WP for sender. I think I pulled a factory plug and It was plug and play.

 

[dadsbee]

40 and 34 are read from sender - connected ohm meter read ohms and made photos of gauge
25 is feeded by connecting 4 resistors that create 25ohm reading into sender wire.

And you connected these resistors where? Between the sender terminal and wire connector or block ground and wire?

 

[davek]

this might help 440 aftermarket temp sender location

 

[rdstudio]

And you connected these resistors where? Between the sender terminal and wire connector or block ground and wire?

between sender plug and block ground / battery ground (same values)

 

[Don67Satellite]

I use a TS17T (which is apparently the low-rent version of the TS17) for the dash gauge and I have a AutoMeter temp gauge.

Both senders are in the WP housing. I use a 180 T-Stat.

After going through 2 previous dash gauge senders that were the wrong ones, I kept the AutoMeter hooked up to see how things look with the TS17T.

With my improved cooling the AutoMeter hits maybe 190 on an extremely hot day idling, but mostly is at 180.

My dash gauge seems to move with these fluctuations as 180 reads just under centre on the factory gauge, and if things move up to 190 it's basically right at centre, both readings in the factory gauge "good zone".

The '67 gauge doesn't have numbers like your Charger, however.

Did you use a ton of thread sealer on the sender? It does need to ground itself to the housing from what I understand.

 

[rdstudio]

Did you use a ton of thread sealer on the sender? It does need to ground itself to the housing from what I understand.

No, it was factory installed teflon tape only on half of thread. So I just threaded it in.

Also ordered Auto Meter today and will see what are real temps of my coolant.